The invention relates to a mixing machine comprising a mixing head having element(s) for connecting it to a receptacle, forming a closed mixing container containing the material to be mixed. The mixing head is pivotably supported opposite a frame in such a manner that the mixing container can pivot for carrying out the mixing process, in which mixing head at least one rotationally driven mixing tool is arranged whose drive shaft extends through the wall of the mixing head. Furthermore, the invention relates to a liner, preferably for such a mixing head.
Such mixing machines concern industrial mixers which are used for mixing in particular bulk material, typically powdery bulk material, such as mixtures of plastic granulates or also in the color industry. These mixing machines comprise a mixing head pivotably supported opposite a frame. The mixing head also closes a receptacle connected to the mixing head forming this mixing container. After the receptacle has been connected to the mixing head a closed mixing container is formed. The mixing head comprises one or more connecting elements for connecting the receptacle to the mixing head, for example a circumferential flange. These mixers are also known as container mixers. The receptacle is also known as a mixing container. The mixing head itself is pivotably arranged opposite the machine frame of the mixing machine so that the mixing takes place as regards the mixing head in an upside down position in which the mixing head is at the bottom and the mixing container connected to it is at the top. In this position the bottom discharge opening of the mixing container faces upward.
This upside down position is required so that the material comes in contact with the at least one mixing tool carried by the mixing head. The rotationally driven mixing tool serves to generate a flow of material to be mixed inside the closed mixing chamber. The time of the mixing procedure determines the degree of mixing. Such an industrial mixer is known, for example, from EP 0 225 495 A2.
In such mixing machines the material is mixed in batches in the mixing receptacle formed by the mixing container and the mixing head. If the composition of the material of the material to be mixed is different between a first batch and a subsequent batch the mixing head must be cleaned. This requires a cleaning of the inner wall of the mixing head and of the mixing tool or mixing tools arranged in it. To this end to the mixing tools can be and are removed from the mixing head.
Therefore, it should be noticed in mixing machines of this type that accumulations of mixing material form in the mixing head, in particular in the area around the mixing tool or tools which accumulations can also adhere to the bottom of the mixing machine depending on the material to be mixed. These accumulations of material form already at the beginning of the mixing process with the consequence that this material is decoupled from the further mixing process. This can occur in mixing heads that have a slowly rotating first tool that typically cleans the bottom and comprise one or more rapidly rotating mixing tools such as are known, for example, from DE 20 2014 101 787 U1 or from DE 20 2009 001 937 U1. A mixing of mixing material without an appreciable charging of heat is possible with these mixing heads. Since in mixing machines with such mixing heads the mixing takes place in an upside down arrangement with mixing tools at the bottom, during the pivoting back of the mixing head into the starting position after the conclusion of the mixing procedure for decoupling the mixing container this material that was not sufficiently mixed falls onto the properly mixed mixing material located below it. Even if the amount of this falling, insufficiently mixed mixing material is in the final analysis not appreciable as regards the amount of the properly mixed mixing material, it occasionally is apparent due to its color which differs in comparison to the properly mixed mixing material. Moreover, it is undesirable if even slight amounts of mixing material are not properly mixed. In addition, it can be disadvantageous if such insufficiently mixed material adheres in the mixing head and remains in it as an unmixed or insufficiently mixed accumulation of material.
Starting from this discussed prior art, the invention therefore has the problem of further developing a mixing machine of the initially cited type so that mixing material can be properly mixed in its entirety with this machine while avoiding the previously outlined problems.
The foregoing example of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.